1. Field of the Invention
The present invention relates to a silicon structure including a silicon substrate that has an electric element and wiring conductors and bonding pads, which are disposed on the silicon substrate and connect the electric element to an external circuit.
2. Description of the Related Art
In a semiconductor pressure sensor (diaphragm type pressure sensor), which is an example of such a silicon structure, the silicon substrate having a plane rectangular diaphragm (over a cavity) is formed, and a plurality of sensitive resistance elements (electric elements) positioned at the edges of the diaphragm and bonding pads connected to the sensitive resistance elements via wiring conductors are disposed on the silicon substrate. The wiring conductors and the bonding pads are made of a metal thin film, most commonly, an aluminum (Al) film.
In the semiconductor pressure sensor, the sensitive resistance elements and the wiring conductors are covered with a protective film (passivation film), but the bonding pads are exposed for wire-bonding with an external circuit. That is, the protective film has pad opening patterns corresponding to the bonding pads.